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Abstract
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Wastewater containing synthetic dyes originating from diverse industries causes significant risks to both ecological systems and public health. This study investigates a novel approach to methylene blue dye's photocatalytic/absorptive process by combining centrifugal spun polycaprolactone (PCL) containing zinc and palladium sulfide as photocatalysts with their favourable band gap. Characterization techniques, including FTIR, XRD, SEM-EDS, and UV-Vis spectrophotometry, confirm the successful formation of a polymeric scaffold with the embedded metal hybrid. According to the kinetic and isotherms models, the degradation rate was observed to follow the pseudo-second-order kinetics model with a good correlation coefficient (R2 = 0.99), and the equilibrium data obtained from the absorption of methylene blue fitted best into the Freundlich isotherm (1/n=-0.37). Results indicate that the three-dimensional centrifugal fibers (diameters less than 2 mu m) with metallic hybrid particles prepared by the solvothermal method exhibit superior performance to 2D conventional spun fibers. This is attributed to increased surface area and uniform distribution of size-controlled metal sulfides, leading to enhanced interaction with the dye. Furthermore, the fibers demonstrate potential for sustainable water treatment purposes, as they can remain afloat on water, thus allowing for reusability while exhibiting a gradual decline in effectiveness over multiple recycling processes. Also, thermodynamic calculations have shown that the absorbance of methylene blue as a pollutant on the centrifuged electrospun fibers with ZnS/PdS after 3 h is chemically with Delta H=132.17 and Delta G=-13.98 kJ/mol.
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